It is desirable to manufacture a radiotelephone having two transceivers which are operative respectively in, by example, the 1900 MHz and 850 MHz frequency bands. By example, the 1900 MHz band may be used for TDMA (digital) communications, such as that specified by IS-136 or DCS1900 MHz of PCS, while the 850 MHz band may be used for analog (e.g., AMPS) communications. Such a radiotelephone requires a diplexer for separating RF (radio frequency) signals at the 1900 MHz and 850 MHz bands. The diplexer connects the antenna, typically in the form of a rod, with the two transceivers in the radiotelephone, one transceiver being operative at 1900 MHz and the other transceiver being operative at 850 MHz.
The addition to the radiotelephone of a further electrical component, such as a diplexer having a conventional configuration, may necessitate an increase in the physical size of the radiotelephone. This would create a problem in that it is generally desirable to decrease, rather than to increase the size of the radiotelephone. Thus, there is a need to fabricate the diplexer in a manner which avoids excessive increase in the size of the radiotelephone.